Features and Benefits
- PolyPhase® Controller Reduces Input and Output Capacitance and Power Supply Induced Noise
- Wide VIN Range: 4.5V to 38V Operation
- ±0.75%, 0.6V Reference Voltage Accuracy
- High Efficiency: Up to 95%
- Programmable Burst Mode® Operation or Stage Shedding™ for Highest Light Load Efficiency
- Active Voltage Positioning (AVP)
- RSENSE or DCR Current Sensing
- Programmable DCR Temperature Compensation
- Phase-Lockable Fixed Frequency: 250kHz to 770kHz
- True Remote Sense Differential Amplifier
- Dual N-Channel MOSFET Synchronous Drive
- VOUT Range: 0.6V to 5V without Differential Amplifier
- VOUT Range: 0.6V to 3.3V with Differential Amplifier
- Adjustable Soft-Start or VOUT Tracking
- Stackable for Up to 12-Phase Operation
- 32-Pin (5mm × 5mm) QFN and 38-Pin TSSOP Packages
The LTC3856 is a single output, dual channel PolyPhase synchronous step-down DC/DC controller that drives all N-channel power MOSFET stages. This device includes a high speed differential amplifier for remote output voltage sense. Power loss and supply noise are minimized by operating the two controller output stages out-of-phase and up to 12-phase operation can be achieved.
The LTC3856 monitors the output current by sensing the voltage drop across the output inductor (DCR) or by using a sense resistor. DCR temperature compensation maintains an accurate current sense threshold over a broad temperature range. A constant-frequency, current mode architecture allows a phase-lockable frequency of up to 770kHz.
A wide 4.5V to 38V input supply range encompasses most intermediate bus voltages and battery chemistries. Burst Mode operation, continuous or Stage Shedding modes are supported. A TK/SS pin shared by both channels ramps the output voltage during start-up.
- Telecom and Datacom Systems
- Industrial and Medical Instruments
- DC Power Distribution Systems
- Computer Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 1580A is a high efficiency, polyphase, synchronous buck converter with a 4.5V to 14V input range. It can supply 50A maximum load current at 1.5V output. The demo board uses the LTC3856EUH controller. The LTC3856 is a feature-rich single-output dual-phase synchronous buck controller with on-chip drivers and remote differential output voltage sensing. This board is setup with sense resistor configuration with optional inductor DCR sensing circuit.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
Design tools for the following parts are available in LTpowerCAD:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.